"We might go a lifetime without seeing this magnitude" again, ornithologist Mark B. Robbins at the University of Kansas Biodiversity Institute, told the paper. "I recognized pretty quickly that when things started happening early ... this was a pretty big invasion."

The AP explains it's result of a big population of Arctic lemmings — the small rodents often depicted jumping off cliffs en masse — which caused a great breeding season. "Lemmings are snowy owls' main food source, and the baby boom is sending many of the youngsters across the border to scrounge for voles, field mice, rats, rabbits and shore birds," the AP reports.

This probably means, if you're even a little bit of a bird watcher, this is a good winter for a long stroll in the woods. Snowy owls are hard to miss: They have a white face, can be as tall as 2 feet and have a 5-foot wingspan.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.